The modern American diet is mostly made up of "easy calories." According to Gail Civille, a food-industry consultant and the owner of Sensory Spectrum, Americans of the past typically had to chew a mouthful of food as many as 25 times before swallowing; the average American today chews only 10 times.

In part, this is because fat, which has become ubuiquitous, is a lubricant. We don't eat as much lean meat, which requires more saliva to ready it for swallowing. "We want food that's higher in fat, marbled, so when you eat it, it melts in your mouth," says Civille. Food is easier to eat when it breaks down more quickly in the mouth. "If I have fat in there, I just chew it up and — whoosh! — away it goes."

John Haywood, a prominent restaurant concept designer, agrees. Processing, he says, creates a sort of "adult baby food." By processing, he means removing the elements in whole food — like fiber and gristle — that are harder to chew and swallow.

Hmmm. That's certainly plausible, but I still want to know where those exact figures come from. I demand proof.